The present invention relates to the field of cellular wireless communications, and more particularly to a method of controlling the transmission of identities from wireless communications devices from outside the wireless communications device.
In order for a wireless communications network to check whether a particular service subscription is valid, the network must be able to identify the subscription. Typically this is done by-having the wireless communications device provide a unique identifier to the network when requesting service. For instance, in a typical ANSI-41/ANSI-136 network, a cellular phone transmits its Electronic Serial Number (ESN) when the phone performs any one of a variety of wireless communications control functions, such as registration or call origination. While providing the subscription identity may be required in some instances, in others it merely consumes control channel transmission capacity without a real benefit. In order to lessen the burden on the network, ANSI-136 provides the network with a way of controlling the transmission of the identity. The ANSI-136 solution is to provide a broadcast control bit, known as the xe2x80x9cSxe2x80x9d bit, that the network may selectively turn on or turn off. When the S-bit is turned on, the wireless communications devices directly interacting with the network are required to transmit the identity when performing any of the wireless communications control functions known generally as registration, origination, page response, base station challenge order, R-data (teleservices), and SPACH confirmation. In essence, the existing ANSI-136 networks are able to turn on the identity transmission for all of these control functions or for none of these control functions, but nothing in-between. As such, if the network only needs the identity for one of the control functions, it must turn on the identity transmission for all of the control functions, thereby burdening the control channel with unnecessary traffic. Thus, there is a need for a method of controlling the transmission of device identity that provides the network with a greater level of flexibility in asking for the identity of the wireless communications device.
Further, it is possible that wireless communications devices will have more than one identity. Traditionally, a wireless communications device had one unique fixed identity in ANSI41/ANSI-136 networks. In the ANSI-136 nomenclature, this was the ESN. The wireless communications device was manufactured with this ESN, which under FCC regulations cannot be altered after manufacture. The traditional ANSI-41/ANSI-136 service subscription was then tied to a particular wireless communications device, typically by including the ESN as part of the subscription information necessary to identify the user to the network. Thus, the traditional ANSI41/ANSI-136 subscriber could not use a different piece of equipment, such as another user""s phone handset, for the same subscription.
The situation with traditional ANSI41/ANSI-136 is to be contrasted with that under the standard known as Global System for Mobile Communication (GSM). In the GSM world, a wireless communications device has two functional parts, a subscription module and a mobile terminal. The subscription module, commonly known as either the Subscriber Identity Module (SIM), the SIM card, or a User Identity Module (UIM), may be thought of as an electronic identification card; it contains the subscription-related information required to verify the subscriber to the network. The SIM card typically includes memory and other electronics for performing a variety of functions, but the SIM card does not include the transceiver electronics necessary for the main GSM wireless communications. For reference, see GSM 11.11 and GSM 11.14 for SIM card specifications in the GSM network. Relevant to the present discussion, the SIM card contains a fixed subscription identifier, similar to that of the ESN of ANSI-136. For ease of reference, this identifier will be referred to as the ESNs.
The mobile terminal is the rest of the wireless communications device without the subscription module. Thus, the mobile terminal is the handset or other main unit that includes the main GSM transceiver circuits, the speaker, etc. The mobile terminal likewise includes a fixed identifier, which will be referred to as the IMEI or the ESNm.
The GSM subscription module is inserted or otherwise connected to the GSM mobile terminal to form a complete wireless communications device that is useable in GSM. The subscription information is read from the subscription module by the mobile terminal and transmitted to the network where the network determines whether the subscription is valid and registers the location of the subscription within the network. Thus, the GSM service subscription is typically not tied to a specific mobile terminal, but rather is tied to the subscription module. Because the subscription module authenticates the user to the network, the user is free to use any compliant mobile terminal equipment by simply mating their subscription module to the mobile terminal and repeating the authentication and registration process with the new mobile terminal hardware. Thus, it is not always necessary for the user to carry the complete wireless communications device in order to access his/her wireless service subscription. Instead, the user need only carry the subscription module and mate the module to an appropriate mobile terminal available on-location.
In GSM, there is a provision for the network to request that the wireless communications device send the ESNm of the mobile terminal, typically for purposes of tracking lost or malfunctioning mobile terminals. The process for this in GSM is for the GSM network to make contact with a particular wireless communications device and request that particular wireless communications device to send its ESNm. There is no provision in GSM for the network to tell a plurality of wireless communications devices to send the ESNm when performing regular control functions; rather, a separate request must be made to each wireless communications device in turn. Thus, there remains a need for a method of controlling the transmission of identities associated with wireless communications devices.
The idea of allowing the use of small, inexpensive subscription modules, similar to SIM cards, is gaining favor in the ANSI-41/ANSI-136 world due to the desire for subscription mobility. However, traditional ANSI-41/ANSI-136 contemplates the existence of only one fixed identity per wireless communications device, not two. Quite simply, ANSI41/ANSI-136 anticipates that the equivalent to the subscription module will always be mated to the same mobile terminal, and will not be portable between mobile terminals, therefore only one fixed identity is required per wireless communications device. Because subscription-module-enabled wireless communications devices will have two fixed identities, ANSI41/ANSI-136 networks may need to be modified to accommodate the presence of more than one fixed identifier associated with a wireless communications device. For instance, the network may need the identity of the subscription module for, some control functions and the identity of the mobile terminal for others. Thus, there is a need for an improved ANSI41/ANSI-136 protocol that accommodates the presence of more than one fixed identifier associated with a wireless communications device. Such a method should preferably allow the network to request one of the identities be provided by the wireless communications device during some control functions, and another identity during other control functions. Preferably, the method should be flexible so that one wireless communication""s network can request the first identity for a particular set of wireless control functions, while another wireless communications network can request the first identity for a different set of wireless control functions.
From the above, it is clear that there remains a need for an improved method of controlling the transmission of identities from wireless communications devices in wireless communications networks. Such a method should provide the network with a high degree of flexibility in asking for selected identities from the wireless communications device. Optionally, the method may allow the network to instruct the wireless communications devices to transmit one identity in some situations and another in other situations.
The present method relies on a broadcast message from the network to instruct the wireless communications devices as to when to send their identity information, with control being extended to the control function class level. In a simple embodiment, the network includes instructions in a broadcast message telling the receiving wireless communications devices to send their identities for some classes of control functions and not others. Thus, by altering the broadcast message, the network is able to control the identity transmissions of the wireless communications devices. In more sophisticated embodiments, the network can control not only whether identities are transmitted for certain control functions, but which identity is transmitted. Thus, one identity (e.g., subscription module identifier) may be transmitted with one class of control functions (e.g., registration) and another identity (e.g., mobile terminal identifier) to be transmitted with other classes of control functions (e.g., page response), thereby providing great flexibility of control to the network.